Nodular hidradenoma of the caruncle.

An 84-year-old man presented with a tumor of the right caruncle causing epiphora due to insufficient eyelid closure. The tumor was cystic and mucinous in appearance. MRI showed a solitary tumor of the caruncle with no adhesions to neighboring tissue. The mass was removed by carunculectomy. Histopathologic examination revealed a tumor composed of epithelial cells with intervening strands of hyalinized stroma. Solid areas were predominant but a cribriform area could also be distinguished. Periodic acid-Schiff positive, diastase-labile material (glycogen) was detected in many tumor cells. Immunohistochemical staining of the tumor cells demonstrated positive staining with antibodies against CK-CAM 5.2, BER-EP4, p63, and smooth muscle actin-positive cells in some areas. The tumor was diagnosed as a nodular hidradenoma of the caruncle, which has never been reported before and should be included in the diagnoses of caruncular tumors.